vendor: Update vendoring for the exec client and server implementations

Signed-off-by: Jacek J. Łakis <jacek.lakis@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

vendor/github.com/kr/pty/pty_unsupported.go

@@ -0,0 +1,11 @@
+// +build !linux,!darwin,!freebsd,!dragonfly
+
+package pty
+
+import (
+	"os"
+)
+
+func open() (pty, tty *os.File, err error) {
+	return nil, nil, ErrUnsupported
+}